1. Field of the Invention
The present invention relates generally to fabrication of recording heads of disk drive assemblies, and more particularly to use of Deep Reactive Ion Etching in component fabrication.
2. Description of the Prior Art
Conventional magnetic recording head sliders are typically made from wafers of a two-phase ceramic, TiC/Al2O3, also called Al—TiC. After the thin film processing to prepare the recording heads is performed on the Al—TiC wafers, the sliders are then formed. The sliders are fabricated by cutting, grinding and lapping the wafer made of the above material. Normally, as shown in FIGS. 1–2C (Prior Art), the wafer 2 is first cut into pieces which are then cut into the slider bodies 4. The sliders bodies 4 are prepared by diamond sawing in three separate sawing steps: (i) coarse sawing to divide the wafer 2 into smaller pieces, called quadrants 6, (ii) row sawing to separate rows 8 of slider bodies 4 from the wafer quadrants 6; these rows 8 are then lapped, and (iii) slider separation sawing to separate the completed sliders 4 from the rows 8. This process has evolved considerably with time, but still suffers from inherent limitations associated with the diamond sawing process, such as the fairly wide ‘kerf’ needed for the passage of the blade, edge chipping, generation of surface damage, and generation of loosely-bound particles which may become dislodged in the disk drive. These limitations impact the number of heads which can be put on a finished wafer, the yield of acceptable finished sliders and the reliability of the disk drive itself.
An alternative processing approach is available for Si substrates. This is the process known as DRIE (Deep Reactive Ion Etching) which has been developed during the last 8 years, to give a technique, and associated commercially available tooling, which allows the very deep, high aspect ratio etching of Si. For example, material thicker than 1 mm has been etched with aspect ratios (ratio of depth of cut to width of cut) of about 20. This is a two-stage one process in which the material is etched for a few seconds and then passivated a few seconds, so that at the bottom of the trench being etched, the passivation is removed more rapidly than along the adjacent trench walls, thereby focusing the etching action at this point during the etch cycle. DRIE tools are common, commercially, and are used in fabricating MEMS (Micro Electromechanical Systems) structures, such as Si-based accelerometers.
Thus there is a need for a fabrication which does not have the disadvantages discussed above caused by mechanical methods of separation such as sawing.